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  #1  
Old January 6th, 2018, 22:04
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8.25 axle question

I wanted to check before I go ahead and do it.

My rear 8.25 is bent .75 of a degree on the passenger side since about 10 years ago.

I finally bought a junkyard 8.25 and all 110 lb's of me dragged it into my car and home. LOL that was fun.

the car it came out of had no engine or transmission and i did not check the vin to find out what engine was in it. it was a 96-00 xj tho.

I have a 92 laredo 4.0 with the aw4
Do I have to worry about the other 8.25 having different gears ?
and how is the easiest way to figure it out.
I know there is a 29 and 27 spline. but that does not matter for this I believe.

been wrenching on cars for years. but axles I am kinda new to axles and swapping them.
thanks for any info.
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  #2  
Old January 6th, 2018, 23:26
trippled trippled is offline
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Re: 8.25 axle question

Best thing as with any jy axle, pull the cover and check the ring gear numbers. There should be something like 41 10 which is a 4.10 gear ratio, or countthe teeth to figure it out.
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  #3  
Old January 6th, 2018, 23:31
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Re: 8.25 axle question

Okay.
is there a way to tell what my xj has short of pulling the cover ?
I got a 92 with the 8.25 rear aw4 242
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  #4  
Old January 7th, 2018, 06:16
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Re: 8.25 axle question

The most reliable way is to pull the cover and look at the numbers stamped into the ring gear.
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  #5  
Old January 7th, 2018, 07:13
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Re: 8.25 axle question

Quote:
Originally Posted by blu3fan View Post
Okay.
is there a way to tell what my xj has short of pulling the cover ?
I got a 92 with the 8.25 rear aw4 242
If you email Jeep customer service your VIN they will tell you what it was built with
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  #6  
Old January 7th, 2018, 08:33
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Re: 8.25 axle question

Quote:
Originally Posted by Hypoid View Post
The most reliable way is to pull the cover and look at the numbers stamped into the ring gear.
This advice applies to just about any repairs/replacements when the necessary technical info is actually critical info for the success of the project. There is no way to determine what sort of parts swapping has been done in the vehicles past ownership and maintenance. Build sheets that detail the installed components by decoding the VIN are not typically available for early 1990's and older Cherokees, unless you find the actual build sheet inside your Cherokee. Early Chrysler build sheets often contain nonsensical "options" because the option codes were recycled during later model years.


blu3fan, simply open the diff cover on both axles and read what the gears are stamped. You should also perform an inspection of the condition of the gears and shims before you begin the swap. What if you bought an axle that is damaged and you waste all that time and effort for nothing ?








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Last edited by Tim_MN; January 7th, 2018 at 08:54.
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  #7  
Old January 7th, 2018, 09:31
Heavyopp Heavyopp is offline
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Re: 8.25 axle question

This isn't extremely accurate but it will give you a decent guess

Prop the axle up so you can rotate both tires or hubs if no tires

Mark the housing so you can count # of rotations of the Yoke

Spin tire 1 complete rotation, counting rotation of spindle -- 1 full turn of tire and 3 plus a little is 3.07 -- 1 tire rotation and 3 and 3/4 rotation of yoke is 3.73 -- 1 rotation of tire and 4 and a little is 4.10

Not very accurate but will get you in the ballpark -- But you bought an unknown junkyard rear -- pull cover and check -- you really should no matter what -- could be filled with mud
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  #8  
Old January 7th, 2018, 12:07
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Re: 8.25 axle question

You want to open up and inspect the internals of any used axle you buy anyways (as well as change the fluid), so open it up and count the gears or look for the stamp.
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  #9  
Old January 7th, 2018, 13:53
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Re: 8.25 axle question

My main reason for asking is so that when I go to swap it.
I am not out of a car for a day due to having to swap internals.
this is my daily.
the info about checking with jeep about my vin is a great idea
I can pull the Junkyard axle apart and compare.
thanks guys
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  #10  
Old January 7th, 2018, 16:07
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Re: 8.25 axle question

Inspect the axle you bought and determine the gear ratio and condition of the internal parts. If it all checks out, put the cover back on and fill it with gear oil. On the work day, pull the diff cover on the existing differential, and determine the gear ratio. If the ratios match, proceed with the swap, if the ratios do not match, put the cover back on and re-fill it with gear oil. Unless you have the necessary specialized tools and technical knowledge you will not be swapping any internal parts from one axle to the other.

I suggest you inspect and service the brakes before the swap, and that you buy a set of new u-bolts also.
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Quote:
Originally Posted by bimmerjeeper

Blanket caught in the rear liftgate latch. Now I can't open.
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  #11  
Old January 7th, 2018, 18:26
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Re: 8.25 axle question

Quote:
Originally Posted by Tim_MN View Post
Inspect the axle you bought and determine the gear ratio and condition of the internal parts. If it all checks out, put the cover back on and fill it with gear oil. On the work day, pull the diff cover on the existing differential, and determine the gear ratio. If the ratios match, proceed with the swap, if the ratios do not match, put the cover back on and re-fill it with gear oil. Unless you have the necessary specialized tools and technical knowledge you will not be swapping any internal parts from one axle to the other.

I suggest you inspect and service the brakes before the swap, and that you buy a set of new u-bolts also.
I read you telling me not to swap the two if they are different.
but I will....
I built my 4.6 stroker myself.
Nothing is impossible. the internet is vast with information..
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  #12  
Old January 7th, 2018, 19:41
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Re: 8.25 axle question

It certainly can be done, but be aware that you will need a bunch of somewhat specialized tools. Among other challenges, the 8.25 has a pair of large nuts which are used to set the side preload on the bearings. These nuts are accessed through the sides of the axle housing. IOW, a long tool is needed in order to reach in through the brake flange end of the equation.

It would be in your best interest to first figure out what your own axle ratio is (probably 3.55) and then also figure out the ratio and general condition inside the second axle. It the donor vehicle was a 4.0 with a stick shift it should have 3.07 gears (Just an example of a likely difference). And yes, the internal picture could also be a train wreck.

You are getting good answers to your questions (and they are some of the right questions to be asking).

Do I have to worry about the other 8.25 having different gears ?--Yes

and how is the easiest way to figure it out.--See earlier posts describing different methods.

I know there is a 29 and 27 spline. but that does not matter for this I believe.--Not if you swap complete axles, but it will start to matter if you try to swap some components, but not others. If you were to swap all internals things should go fine, but if one axle shaft is bent from the damage to your old housing you will not be able to not swap that shaft thinking you will use one shaft from the old and one from the new. (I hope that makes sense...)
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  #13  
Old January 7th, 2018, 21:49
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Re: 8.25 axle question

Quote:
Originally Posted by Anak View Post
It certainly can be done, but be aware that you will need a bunch of somewhat specialized tools. Among other challenges, the 8.25 has a pair of large nuts which are used to set the side preload on the bearings. These nuts are accessed through the sides of the axle housing. IOW, a long tool is needed in order to reach in through the brake flange end of the equation.

It would be in your best interest to first figure out what your own axle ratio is (probably 3.55) and then also figure out the ratio and general condition inside the second axle. It the donor vehicle was a 4.0 with a stick shift it should have 3.07 gears (Just an example of a likely difference). And yes, the internal picture could also be a train wreck.

You are getting good answers to your questions (and they are some of the right questions to be asking).

Do I have to worry about the other 8.25 having different gears ?--Yes

and how is the easiest way to figure it out.--See earlier posts describing different methods.

I know there is a 29 and 27 spline. but that does not matter for this I believe.--Not if you swap complete axles, but it will start to matter if you try to swap some components, but not others. If you were to swap all internals things should go fine, but if one axle shaft is bent from the damage to your old housing you will not be able to not swap that shaft thinking you will use one shaft from the old and one from the new. (I hope that makes sense...)
Makes sense.
Worst case scenario I can get those 4.11 gears with the lunchbox locker ive been looking at :P
I mean if I havveee to spend the money

Last edited by blu3fan; January 7th, 2018 at 21:54.
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  #14  
Old January 7th, 2018, 21:53
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Re: 8.25 axle question

Quote:
Originally Posted by blu3fan View Post
Makes sense.
Worst case scenario I can get those 4.10 gears with the lunchbox locker ive been looking at :P
I mean if I havveee to spend the money
Yup, XJs are like a box 'o chocolates!
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  #15  
Old January 8th, 2018, 08:06
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Re: 8.25 axle question

Quote:
Originally Posted by blu3fan View Post
Makes sense.
Worst case scenario I can get those 4.11 gears with the lunchbox locker ive been looking at :P
I mean if I havveee to spend the money
Be aware that a lunch box locker is where many people run up against an annoying reality with these axles. You cannot use a lunch box to convert a 27 spline carrier to 29 spline. You also cannot put a lunch box in a limited slip carrier.

Call that one more reason to figure out what you really have before you spend any money going a particular direction.
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